A plant-based meal affects thalamus perfusion differently than an energy- and macronutrient-matched conventional meal in men with type 2 diabetes, overweight/obese, and healthy men: A three-group randomized crossover study

Abstract

Reward circuitry in the brain plays a key role in weight regulation. We tested the effects of a plant-based meal on these brain regions. A randomized crossover design was used to test the effects of two energy- and macronutrient-matched meals: a vegan (V-meal) and a conventional meat (M-meal) on brain activity, gastrointestinal hormones, and satiety in participants with type 2 diabetes (T2D; n=20), overweight/obese participants (O; n=20), and healthy controls (H; n=20). Brain perfusion was measured, using arterial spin labeling functional brain imaging; satiety was assessed using a visual analogue scale; and plasma concentrations of gut hormones were determined at 0 and 180min. Repeated-measures ANOVA was used for statistical analysis. Bonferroni correction for multiple comparisons was applied. The Hedge's g statistic was used to measure the effect size for means of paired difference between the times (180-0min) and meal types (M-V meal) for each group. Thalamus perfusion was the highest in patients with T2D and the lowest in overweight/obese individuals (p=0.001). Thalamus perfusion decreased significantly after ingestion of the M-meal in men with T2D (p=0.04) and overweight/obese men (p=0.004), and it decreased significantly after ingestion of the V-meal in healthy controls (p<0.001; Group x Meal x Time: F=3.4; p=0.035). The effect size was-0.41 (95% CI,-1.14 to 0.31; p=0.26) for men with diabetes;-0.72 (95% CI,-1.48 to 0.01; p=0.05) for overweight/obese men; and 0.82 (95% CI, 0.09 to 1.59; p=0.03) for healthy men. Postprandial secretion of active GLP-1 increased after the V-meal compared with the M-meal by 42% (95% CI 25-62%; p=0.003) in men with T2D and by 41% (95% CI 24-61%; p=0.002) in healthy controls. Changes in thalamus perfusion after ingestion of both test meals correlated with changes in satiety (r=+0.68; p<0.01), fasting plasma insulin (r=+0.40; p<0.01), C-peptide (r=+0.48; p<0.01) and amylin (r=+0.55; p<0.01), and insulin secretion at 5mmol/l (r=+0.77; p<0.05). The higher postprandial GLP-1 secretion after the V-meal in men with T2D, with concomitant greater satiety and changes in thalamus perfusion, suggest a potential use of plant-based meals in addressing the key pathophysiologic mechanisms of food intake regulation. Trial registration ClinicalTrials.gov number, NCT02474147.